There are disclosed conventional endless track magnetic traveling devices as a technology of this type in JP-A47-40635, JP-A51-79498, JP-A 56-79069, JP-A 60-18464, JP-A61-89184, etc., wherein the endless track magnetic traveling device is used as various devices depending on its purpose, for example, an apparatus such as an ultrasonic inspection device.
The conventional endless track magnetic traveling devices set forth above can travel smoothly on a horizontal surface having no uneven spot on the traveling surface, thereby performing an excellent traveling performance. However, these conventional endless track magnetic traveling devices have not considered the traveling surface having an uneven spot.
Further, these conventional devices comprise a vehicle body and two endless tracks which have the same dimensions and are provided at both sides of the vehicle body.
In the conventional endless track magnetic traveling device set forth above, there are following problems to be solved.
First, in the conventional traveling devices of this type, connecting portions for connecting each magnet constituting each endless track are needed to be loosened to have the slack so as to get over the uneven spot of the traveling surface. That is, when there is the slack on each connecting portion, the traveling device can travel on a ceiling surface 60 having an uneven spot 60a as shown in FIG. 58. However, since the weight of the traveling device including driving wheels 93 is applied to magnets 91 located adjacent to both ends of the endless tracks at the front and rear thereof in the traveling direction but not applied to the magnets constituting the endless tracks comprising a combination of the magnet 91 and the chain 92 when traveling on the ceiling surface 60, it is not assured that the danger of falling of the traveling device is sufficiently avoided.
Accordingly, in the conventional traveling device having such a wall surface moving mechanism, it is necessary to increase attraction of each magnet. This is solved by taking a measure, for example, as disclosed in a traveling device of JP-A47-40635 wherein an interval between driving wheels 93 is widened by a spring 94 (FIG. 59), and an endless track is extended in the traveling direction thereof. However, when the endless track is extended, the traveling performance is decreased on the uneven spot of the traveling surface so that the weight of the traveling device can not be supported by all the magnets 91 by way of a chain 92 when traveling on the uneven spot 60a of the ceiling surface 60 as shown in FIG. 60. As a result, there occurs a possibility of the falling of the traveling device. Further, the endless track can not be extended in the traveling direction (to widen the interval between the driving wheels 93) unless the magnets 91 attracted to the traveling wall surface are slid.
To solve the aforementioned problems of the traveling device when traveling on the ceiling surface, a traveling device as disclosed in JP-A 63-90484 has a load dispersion type crawler in which magnets are supported by a guide plate fixed to a traveling device body, so that it can not get over the uneven spot easily.
In the conventional traveling device as disclosed in JP-A61-89184, as shown in FIG. 61, a buffer member( which is not shown but covering an outer periphery of a magnet 91) is provided between magnets 91 and a chain 92 respectively constituting an endless track so as to press the magnets 91 against a traveling surface 60. However, a sufficient stroke is not assured by merely pressing the magnets 91 against the traveling surface 60 with the buffer member between the link-shaped endless track and the traveling surface 60. Accordingly, the traveling device does not sufficiently travel on the traveling surface 60 having a curvature of a large uneven spot such as a weld bead. Still further, since there is no mechanism for pressing the chain 92, and the magnets 91 and the chain 92 are connected to one another by pins 95, the magnets 91 have large freedom in their movement, namely, they are movable largely, leading to a possibility that the magnets 91 interfere with one another.
More still further, there is disclosed in a traveling device in JP-A 2-92788 wherein a linear actuator is disposed on a crawler 1a (traveling device comprising an endless track) which is actuated when a sensor detects the uneven spot 60a of the traveling surface 60 so that the traveling device gets over the uneven spot 60a of the traveling surface 60. This has however the problem that the traveling device becomes large scaled, and the magnets of the endless tracks 97 do not slide at the portion where they are attracted to the traveling surface 60 as denoted by A in FIG. 62. Accordingly, it is necessary to supply endless track to the front of the traveling direction by the length corresponding to the portion where they are recessed at the uneven spot 60a of the traveling surface 60. However, there is not taken sufficient measure to cope with this problem.
Whereupon, there is an invention for a traveling device which travels on a wall surface having a curvature and is disclosed in JP-A3-231079 in which the magnets of the crawler travel along a gap between a guide rail so that the guide rail meeting the curvature must be prepared every time it is needed, which generates a replacement operation.
The conventional crawler comprises, as disclosed in FIG. 63 (a) which is a plan view of the crawler and in FIG. 63 (b) which is a side view, a single body 98 and two endless tracks 97 which are arranged in parallel with each other. The traveling of these endless tracks 97 is controlled by a driving source (not shown) by way of driving wheels 93 so that the traveling device can be operated to be traveled to the right or left or turned. Accordingly, the capacity and the range of application of the traveling device are restricted in view of the structure thereof. Further, in a traveling device as shown in FIGS. 64 (a) and (b), a longitudinal direction of a motor 99 for the driving wheels 93 of each endless track 97 crosses at right angles with the traveling direction of the traveling device, and the motor 99 is arranged inside a vehicle body 98, so that the driving wheels 93 are positioned at the front and rear of the body 98, causing a possibility of occurrence of unstable movement such as the swinging to the right or the left owing to the backlash at each endless track 97 when the traveling device starts the traveling.
Although it is a known technique to perform remote control when mounting a battery or a generator on a vehicle body, there was a problem that battery or the generator is too heavy to be mounted on the magnet crawler, and hence it was difficult to be practiced.
Further, the conventional traveling device of this type has another problem that the sliding portion is worn, iron dust is magnetized by the magnet crawler so that iron dust bites into the sliding position, causing a bad influence on the traveling device since the traveling device employs a steel structure.
Accordingly, it is an object of the invention to provide an endless track magnetic traveling device which is improved in traveling performance when traveling on the traveling surface having an uneven spot or a curvature.
It is another object of the invention to provide an endless track magnetic traveling device which is excellent in utilization thereof.
It is still another object of the invention to provide an endless track magnetic traveling device which is excellent in traveling performance in such a manner that it can turn without damaging the traveling surface and also can travel on the traveling surface even at a high temperature.
It is more still another object of the invention to provide an endless track magnetic traveling device capable of traveling by endless tracks which are easily controllable in their traveling.
It is a still other object of the invention to provide an endless track magnetic traveling device which is light-weight.
It is more still other object of the invention to provide a coupling-type endless track magnetic traveling device capable of traveling on a complex traveling surface and capable of changing the number of endless tracks depending on uses thereof.